Thermostatic switch



FIG. 1 is a perspective view of a thermostatic switch showing my new design;

FIG. 2 is side elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof; and

FIG. 5 is an end elevational view thereof. 

The ornamental design for a thermostatic switch, substantially as shown. 